Surface Tension Of Fluid Research Articles

Binary Mixture Droplet Evaporation on Microstructured Decorated Surfaces and the Mixed Stick-Slip Modes.

The interactions between liquid droplets and solid surfaces during wetting and phase change are important to many applications and are related to the physicochemical properties of the substrate and the fluid. In this work, we investigate experimentally the evaporation of pure water, pure ethanol, and their binary mixture droplets, accessing a wide range of surface tensions, on hydrophobic micro-pillared surfaces varying the spacing between the pillars. Results show that on structured surfaces, droplets evaporate following three classical evaporative behaviors: constant contact radius/pinning, stick-slip, or mixed mode. In addition, we report two further droplet evaporation modes, which are a mixed stick-slip mode where the contact angle increases while the contact radius decreases in a stick-slip fashion and a mixed stick-slip mode where both the contact angle and the contact radius decrease in a stick-slip fashion. We name these evaporation modes not yet reported in the literature as the increasing and decreasing contact angle mixed stick-slip modes, respectively. The former ensues because the fluid surface tension increases as the most volatile fluid evaporates coupled to the presence of structures, whereas the latter is due to the presence of structures for either fluid. The duration of each evaporation mode is dissimilar and depends on the surface tension and on the spacing between structures. Pure water yields longer initial pinning times on all surfaces before stick-slip ensues, whereas for binary mixtures and pure ethanol, initial pinning ensues mainly on short spacing structures due to the different wetting regimes displayed. Meanwhile, mixed stick-slip modes ensue mainly for high ethanol concentrations and/or pure ethanol independent of the solid fraction and for low ethanol concentrations on large spacing. Contact line jumps, changes in contact angle and pinning forces are also presented and discussed. This investigation provides guidelines for tailoring the evaporation of a wide range of surface tension fluids on structured surfaces for inkjet printing, DNA patterning, or microfluidics applications.

Cavitation Rheology of Model Yield Stress Fluids Based on Carbopol

Measuring the surface tension of yield stress fluids has remained a critical challenge due to limitations of the traditional tensiometry techniques. Here, we overcome those limits and successfully measure the surface tension and mechanical properties of a model yield stress fluid based on Carbopol gels via a needle-induced cavitation (NIC) technique. Our results indicate that the surface tension is approximately 70 ± 3 mN/m, and is independent of the rheology of yield stress fluid over a wide range of yield stress values σy = 0.5-120 Pa. In addition, we demonstrate that a Young modulus smaller than E < 1 kPa can be successfully measured for Carbopol gels with NIC method. Finally, we present a time-resolved flow structure around the cavity in a host of yield stress fluids, and assess the impact of fluid rheology on the detailed form of flow around the cavity. Interestingly, prior to the critical point associated with cavitation, the yield stress fluid is weakly deformed suggesting that the measured surface tension data reflect the near equilibrium values. Beyond the critical point, the yield stress fluid experiences a strong flow that is controlled by both the critical pressure and the non-Newtonian rheology of the yield stress fluid.

Dynamic well killing method based on Y-tube principle when the drill bit is off-bottom

The design of dynamic well killing parameters lacks theoretical support because the U-tube principle is not applicable while drilling bit is not at the well bottom. We present the Y-tube principle and establish a gas and liquid two-phase flow model with the killing fluid backflow and zero net liquid flow theory in wellbore below the drill bit. A dynamic well killing theory is proposed, and the variations of the well killing parameters are revealed. The results were as follows. (1) The Y-tube was composed of an annular part above the bit, a drillstring part, and a wellbore part below the bit. Gas–liquid flow models in those three parts were established to accurately simulate the dynamic well killing process when the drill bit was off-bottom. (2) Based on these models, the dynamic inflow and outflow curves during the killing period were obtained. The variations of the dynamic well killing parameters were analyzed by comparing the two curves. (3) With the increase of pressure, the critical gas velocity of blowout decreases, while the temperature, density and viscosity of the killing fluid do the opposite. With the increase of temperature, density and viscosity, and the decrease of the wellbore diameter, the bottom hole pressure increases. And it decreases with the decrease of the distance between the bit and wellhead. (4) Considering the actual well killing conditions, it is recommended to increase the critical blowout velocity by increasing the killing fluid surface tension and density, and to change the killing fluid density and viscosity so that the dynamic outflow curve is always above the dynamic inflow curve or the dynamic outflow curve is always above the formation pressure. As a result, the dynamic well killing will be successful when the bit is not at the well bottom.

The effect of Alcanivorax borkumensis SK2, a hydrocarbon-metabolising organism, on gas holdup in a 4-phase bubble column bioprocess.

To design bioprocesses utilising hydrocarbon-metabolising organisms (HMO) as biocatalysts, the effect of the organism on the hydrodynamics of bubble column reactor (BCR), such as gas holdup, needs to be investigated. Therefore, this study investigates the first use of an HMO, Alcanivorax borkumensis SK2, as a solid phase in the operation and hydrodynamics of a BCR. The study investigated the gas holdup in 3-phase and 4-phase systems in a BCR under ranges of superficial gas velocities (UG) from 1 to 3cm/s, hydrocarbon (chain length C13-21) concentrations (HC) of 0, 5, and 10% v/v and microbial concentrations (MC) of 0, 0.35, 0.6g/l. The results indicated that UG was the most significant parameter, as gas holdup increases linearly with increasing UG from 1 to 3cm/s. Furthermore, the addition of hydrocarbons into the air-deionized water -SK2 system showed the highest increase in the gas holdup, particularly at high UG (above 2cm/s). The solids (yeast, cornflour, and SK2) phases had differing effects on gas holdup, potentially due to the difference in surface activity. In this work, SK2 addition caused a reduction in the fluid surface tension in the bioprocess which therefore resulted in an increase in the gas holdup in BCR. This work builds upon previous investigations in optimising the hydrodynamics for bubble column hydrocarbon bioprocesses for the application of alkane bioactivation.

Zinc- and Copper-Doped Mesoporous Borate Bioactive Glasses: Promising Additives for Potential Use in Skin Wound Healing Applications.

In this study, zinc (Zn)- and copper (Cu)-doped 13-93B3 borate mesoporous bioactive glasses (MBGs) were successfully synthesized using nitrate precursors in the presence of Pluronic P123. We benefited from computational approaches for predicting and confirming the experimental findings. The changes in the dynamic surface tension (SFT) of simulated body fluid (SBF) were investigated using the Du Noüy ring method to shed light on the mineralization process of hydroxyapatite (HAp) on the glass surface. The obtained MBGs were in a glassy state before incubation in SBF. The formation of an apatite-like layer on the SBF-incubated borate glasses was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The incorporation of Zn and Cu into the basic composition of 13-93B3 glass led to changes in the glass transition temperature (Tg) (773 to 556 °C), particle size (373 to 64 nm), zeta potential (-12 to -26 mV), and specific surface area (SBET) (54 to 123 m2/g). Based on the K-means algorithm and chi-square automatic interaction detection (CHAID) tree, we found that the SFT of SBF is an important factor for the prediction and confirmation of the HAp mineralization process on the glasses. Furthermore, we proposed a simple calculation, based on SFT variation, to quantify the bioactivity of MBGs. The doped and dopant-free borate MBGs could enhance the proliferation of mouse fibroblast L929 cells at a concentration of 0.5 mg/mL. These glasses also induced very low hemolysis (&lt;5%), confirming good compatibility with red blood cells. The results of the antibacterial test revealed that all the samples could significantly decrease the viability of Pseudomonas aeruginosa. In summary, we showed that Cu-/Zn-doped borate MBGs can be fabricated using a cost-effective method and also show promise for wound healing/skin tissue engineering applications, as especially supported by the cell test with fibroblasts, good compatibility with blood, and antibacterial properties.

Экспериментальное исследование поверхностного натяжения магнитной жидкости и ее основы в магнитном поле

The action of an external magnetic field on a magnetic fluid surface tension is a topical problem that has beenrepeatedly addressed theoretically, with a relatively small number of experimental studies conducted. The purpose of ourwork is systematic experimental research on the surface tension of a magnetic fluid and its non-magnetic liquid base by static and dynamic methods. We carried out a detailed study of the physicochemical properties of a decane-based magnetic fluid with magnetite particles stabilized by oleic acid. The dependences of the surface tension and vis-cosity of the non-magnetic liquid base on the concentration of the stabilizing liquid in it and tem-perature were systematically studied. A modified capillary waves method (CWM) was used to measure the surface tension; the results were verified with data obtained using a high-precision commercial tensiometric device. It is shown that with an increase in the concentration of oleic acid in decane, the surface tension of the solution increases. With an increase in the external vertical magnetic field strength, the surface tension of the decane-based magnetic fluid decreases, which is consistent with theoretical results of other authors. The obtained results confirm the hypothesis about the physical mechanism of the change in the surface tension of amagnetic fluid in a magnet-ic field due to the redistribution of magnetic particles in the near-surface layer.

Research on influencing factors and remedial measures of coal seam water blocking effect

Coalbed methane development primarily relies on hydraulic fracturing and drainage gas extraction processes. The intrusion of external fluids and long-term drainage and extraction contribute to the water blocking effect, which becomes one of the crucial factors affecting production capacity. In this study, the coal reservoir of a certain coalbed methane in Hancheng, Shaanxi Province, was selected as the research object. The experimental method was employed to comprehensively evaluate the correlation between factors such as coal sample moisture content, permeability, porosity, properties of external liquids, and water blocking damage. The results indicated that there was a positive correlation between coal sample moisture content, liquid surface tension, and water blocking damage. On the other hand, coal sample pore permeability characteristics, liquid contact angle with rock samples, and water blocking damage showed a negative correlation. Building upon the aforementioned research, an investigation into remedial measures for water blocking damage was conducted. Additionally, a chemical treatment study using the compound surfactant system JSS-1 as a water-blocking agent was performed to manage the water blocking effect. The results demonstrated that JSS-1 as a water-blocking agent significantly reduced the surface tension of the wellbore fluid and improved its wetting behavior on the coal-rock surface. The laboratory experiments confirmed the capability of JSS-1 in managing the water blocking effect.

Control of liquid metal free surface waves by a magnetic field in the processing of materials

The paper deals with one particular example of Electromagnetic Processing of Materials (EPM) as an efficient and environmentally friendly technology response to the increase in energy consumption driven by the high demand for high-grade materials free from contamination and external agents. EPM is a nonintrusive technology that allows efficient manipulation, monitoring, and control of conducting materials, such as liquid metals, semiconductors, molten salts, and electrolytes. This paper focuses on stabilizing or damping the unwanted waves on the surface of liquid metal in industrial processing, such as strip casting and coating with a uniform and constant magnetic field. The study includes the orientation of the applied magnetic field relative to the free surface, the effects of the depth of the fluid layer, viscosity, and surface tension.

Patterning Behavior of Hybrid Buoyancy-Marangoni Convection in Inclined Layers Heated from Below

Alongside classical effects driven by gravity or surface tension in non-isothermal fluids, the present experimental study concentrates on other exotic (poorly known) modes of convection, which are enabled in a fluid layer delimited from below by a hot plate and unbounded from above when its container is inclined to the horizontal direction. By means of a concerted approach based on the application of a thermographic visualization technique, multiple temperature measurements at different points and a posteriori computer-based reconstruction of the spatial distribution of wavelengths, it is shown that this fluid-dynamic system is prone to develop a rich set of patterns. These include (but are not limited to), spatially localized (compact) cells, longitudinal wavy rolls, various defects produced by other instabilities and finger-like structures resulting from an interesting roll pinching mechanism (by which a single longitudinal roll can be split into two neighboring rolls with smaller wavelength). Through parametric variation of the tilt angle, the imposed temperature difference and the volume of liquid employed, it is inferred that the observable dynamics are driven by the ability of gravity-induced shear flow to break the in-plane isotropy of the system, the relative importance of surface-tension-driven and buoyancy effects, and the spatially varying depth of the layer. Some effort is provided to identify universality classes and similarities with other out-of-equilibrium thermal systems, which have attracted significant attention in the literature.

Hydrophobic and Hydrophilic Solid-Fluid Interaction

We propose a novel solid-fluid coupling method to capture the subtle hydrophobic and hydrophilic interactions between liquid, solid, and air at their multi-phase junctions. The key component of our approach is a Lagrangian model that tackles the coupling, evolution, and equilibrium of dynamic contact lines evolving on the interface between surface-tension fluid and deformable objects. This contact-line model captures an ensemble of small-scale geometric and physical processes, including dynamic waterfront tracking, local momentum transfer and force balance, and interfacial tension calculation. On top of this contact-line model, we further developed a mesh-based level set method to evolve the three-phase T-junction on a deformable solid surface. Our dynamic contact-line model, in conjunction with its monolithic coupling system, unifies the simulation of various hydrophobic and hydrophilic solid-fluid-interaction phenomena and enables a broad range of challenging small-scale elastocapillary phenomena that were previously difficult or impractical to solve, such as the elastocapillary origami and self-assembly, dynamic contact angles of drops, capillary adhesion, as well as wetting and splashing on vibrating surfaces.

Research of a novel fracturing-production integral fluid based on cationic surfactant

Fracturing plays an extremely important role in increasing oil and gas production, however, the fracturing flowback fluid has problems such as large volume, difficult treatment, high processing cost, and environmental pollution. In order to expand the application range and reuse of clean fracturing fluid,a fracturing-production integral fluid based on small molecule surfactants, cetyl trimethyl ammonium chloride (CTAC), salicylic acid (SA) and oleic acid amide methyl hydroxypropyl ammonium chloride (OAMDC) is proposed. At 90 °C the resistance of the fracturing-production integral fluid reached values up to 63.5 mPa·s. The surface and interface tension of the fracturing-production integral fluid broken by crude oil were 28.5 and 8.19 × 10-3 mN/m, respectively. It shows good oil flooding ability (up to 16.35 %), static oil washing rate (up to 21.5 %) and outstanding emulsification effect. Meanwhile, the application scope clean fracturing flowback fluid will be expanded to achieve its efficient and comprehensive application in the field of oilfield chemistry, thereby improving the benefits of oilfield development.

High shear strength welding of soda lime glass to stainless steel using an infrared nanosecond fiber laser assisted by surface tension

High shear strength laser welding of glass-to-metal connections are significant in various areas. However, ultrafast laser processing methods are high cost and demanding, while nanosecond laser processing requires clampers to make samples in optical contact. This work proposed an efficient approach based on liquid surface tension in ns-laser welding. Steel and glass were stably bonded together by the surface tension of the interstitial fluid and kept within optical contact (<200 nm). The two materials were welded successfully using a nanosecond fiber laser and the maximum shear strength of 9.74 MPa with a relative standard deviation of 5.3% was obtained. Meanwhile, the welding mechanism was discussed. Furthermore, a pre-welding method, expanding the available parameters range in nanosecond laser welding, was also investigated to stabilize the optical contact condition for a long time. This work provides a convenient approach for improving efficiency and reliability in laser welding industry.

Combined Surface Light Scattering and Pendant-Drop Experiments for the Determination of Viscosity and Surface Tension of High-Viscosity Fluids Demonstrated for Ionic Liquids

The present study provides a strategy for the determination of the viscosity and surface tension of high-viscosity fluids in the form of ionic liquids (ILs) at equilibrium conditions by combining surface light scattering (SLS) and the pendant-drop (PD) method within one experimental setup. Through the study of the same sample under identical conditions by both methods inside a closed system, the surface tension determined via the PD method can be directly used to evaluate the dynamics of surface fluctuations of ILs with an overdamped behavior probed by SLS for accessing their viscosity. In connection with the SLS experiments, variations in the applied detection geometries in reflection and transmission direction and in the probed wave vectors down to relatively small values were also addressed. The reliability and self-consistency of SLS and the PD method applied within the same sample cell has been proven by investigating the reference fluids tris(2-ethylhexyl) trimellitate (TOTM) and n-dodecane featuring relatively high and low viscosities. For the two studied model ILs of opaque to non-transparent color, i.e., the hydrophobic 1-methyl-3-octylimidazolium hexafluorophosphate ([OMIM][PF6]) and the hydrophilic 1,3-bis(2-(2-methoxyethoxy)ethyl)imidazolium iodide ([(mPEG2)2Im]I), the combination of PD measurements and SLS experiments in reflection direction performed at ambient pressure between (303 and 373) K allowed access to the viscosity and surface tension with typical relative expanded uncertainties of (4 and 2) %. These results agree well with own viscosity data from capillary viscometry and experimental data in the literature, demonstrating the performance of the novel approach for the contactless in-situ measurement of viscosity and surface tension of fluids with relatively high-viscosity such as ILs.

Effect of gas type on miscible enhanced oil recovery at naturally fractured reservoirs: case study-Asmari

In this study, we investigate how miscibility develops in naturally fractured reservoirs. We select and simulate compositionally a sector model of a real and highly naturally fractured reservoir of type 2, and the behavior of the reservoir under the influence of different gases injection, including methane, carbon dioxide, lean and rich gas investigated. The minimum miscibility pressure of each gas and the optimum gas injection rate is determined. The effect of injected gas type on solution gas–oil ratio, surface tension, and viscosity of reservoir fluid studied. Results of this study show that the oil recovery factor in the simulation sector model over 25 years of simulation for the natural depletion scenario is 15.2% while for the miscible gas injection at the optimum injection rate is 16.7, 18.8, 17.46, and 19.4% for methane, carbon dioxide, lean gas, and rich gas respectively. Also, an improvement in the development of miscibility in the case of rich gas injection at this type of natural fractured reservoirs observed.Article HighlightsTo reach the highest RF, Gas Injection rate optimization is necessary at this type of NFRs.Injection of methane and lean gas at higher rates causes faster gas breakthrough and leads to lower ultimately oil.The rich gas shows better miscibility condition than other gases at this type of NFRs.

Effects of bulk elasticity on sheet formation and expansion

The destabilization, fragmentation, and atomization of thin fluid sheets governs processes such as the aerosolization of sneeze ejecta, agrochemical spraying, and fuel injection in liquid rocket engines. Although the evolution, stability, and breakup of fluid sheets composed of a Newtonian liquid has been extensively studied, the morphology and dynamics of viscoelastic fluid sheets remains poorly understood. This manuscript provides a theoretical and numerical framework that integrates the effects of fluid elasticity, surface tension, inertia, and viscosity to predict the morphology, velocity, and stress within stable fluid sheets composed of viscoelastic fluids as a function of the dimensionless Weber, Reynolds, and Weissenberg numbers. We find a non-monotonic behavior in the sheet’s size, velocity, and stress distribution as a function of the ratio between the Weissenberg and the Weber numbers. In particular, a minimum in the sheet’s size and a maximum in the stress occur when such a ratio is of the order of unity. We interpret these results as the consequence of the competing effects of the growth-favoring inertia and the restoring elastic forces acting within the sheet. • We study the dynamics of viscoelastic liquid sheets formed by two impinging jets. • Three dimensionless groups: Weber ( W e ), Reynolds ( R e ), and Weissenberg ( W i ) numbers. • Viscosity, elasticity, inertia, and capillarity are quantified by W e , R e , and W i . • A set of governing equations is developed and solved in terms of W e , R e , and W i . • A non-monotonicity in sheet size and stress is revealed for W i / W e ∼ 1. • The non-monotonicity represents a departure from Newtonian behavior. • At W i / W e ∼ 1, sheets also encounter a maximum in the extensional stress. • W i / W e is the ratio between the fluid relaxation time and the process timescale. • Large W e and low R e induce larger non-monotonicities.

Pattern selection in radial displacements of a confined aging viscoelastic fluid

Intricate fluid displacement patterns, arising from the unstable growth of interfacial perturbations, can be driven by fluid viscoelasticity and surface tension. A soft glassy suspension ages, $i.e.$ its mechanical moduli evolve with time, due to the spontaneous formation of suspension microstructures. The shear and time-dependent rheology of an aging suspension can be exploited to generate a wide variety of interfacial patterns during its displacement by a Newtonian fluid. Using video imaging, we report a rich array of interfacial pattern morphologies: dense viscous, dendritic, viscoelastic fracture, flower-shaped, jagged and stable, during the miscible and immiscible displacements of an aging colloidal clay suspension by Newtonian fluids injected into a radial quasi-two-dimensional geometry at different flow rates. We propose a new parameter, the areal ratio, which we define as the fully-developed pattern area normalized by the area of the smallest circle enclosing it. We show that the natural logarithms of the areal ratios uniquely identify the distinct pattern morphologies, such that each pattern can be segregated in a three-dimensional phase diagram spanned by the suspension aging time, the displacing fluid flow rate, and interfacial tension. Besides being of fundamental interest, our results are useful in predicting and controlling the growth of interfaces during fluid displacements.

Pore network modeling of phase distribution and capillary force evolution during slow drying of particle aggregates

The spatial distribution of the liquid phase plays a crucial role for the damage and the deformation of particle aggregates during convective drying. In this paper, a three-dimensional triangulation pore network model (TPNM) is developed that can readily predict the global drying kinetics of particle aggregates and simulate the liquid phase distribution over time in the void space of aggregates made from spherical primary particles with different size distributions in the micrometer range. The discrete element method (DEM) is used to numerically generate the aggregates, whereby the complementary void space is decomposed into pores and throats using the regular Delaunay triangulation and its dual Voronoi tessellation. A modified version of the classical invasion percolation algorithm is set up to describe the preferential evaporation of the liquid confined in the pores. The liquid phase distribution obtained from isothermal drying TPNM simulations captures the evolution of phase patterns measured experimentally better than the prediction of the classical pore network model (CPNM) and the ring pore network model (RPNM). Local capillary forces caused by both fluid pressure and surface tension are computed over time from the filling state of pores. Taking a monodisperse particle aggregate as a reference, the size and spatial distributions of the primary particles are varied to represent the change in the corresponding void space morphology. The simulation results indicate the impact of the pore-scale heterogeneity on the spatial distribution of the liquid phase as well as the capillary forces during convective drying of particle aggregates.

Evaporation-Induced Self-Assembly of Metal Oxide Inverse Opals: From Synthesis to Applications.

ConspectusInverse opals (IOs) are highly interconnected three-dimensional macroporous structures with applications in a variety of disciplines from optics to catalysis. For instance, when the pore size is on the scale of the wavelength of visible light, IOs exhibit structural color due to diffraction and interference of light rather than due to absorption by pigments, making these structures valuable as nonfading paints and colorants. When IO pores are in an ordered arrangement, the IO is a 3D photonic crystal, a structure with a plethora of interesting optical properties that can be used in a multitude of applications, from sensors to lasers. IOs also have interesting fluidic properties that arise from the re-entrant geometry of the pores, making them excellent candidates for colorimetric sensors based on fluid surface tension. Metal oxide IOs, in particular, can also be photo- and thermally catalytically active due to the catalytic activity of the background matrix material or of functional nanoparticles embedded within the structure.Evaporation-induced self-assembly of sacrificial particles has been developed as a scalable method for forming IOs. The pore size and shape, surface chemistry, matrix material, and the macroscopic shape of the IO, as well as the inclusion of functional components, can be designed through the choice of deposition conditions such as temperature and humidity, types and concentrations of components in the self-assembly mixture, and the postassembly processing. These parameters allow researchers to tune the optical, mechanical, and thermal transport properties of IOs for optimum functionality.In this Account, we focus on experimental and theoretical studies to understand the self-assembly process and properties of metal oxide IOs without (bare) and with (hybrid) plasmonic or catalytic metal nanoparticles incorporated. Several synthetic approaches are first presented, together with a discussion of the various forces involved in the assembly process. The visualization of the deposition front with time-lapse microscopy is then discussed together with analytical theory and numerical simulations to determine the conditions needed for the deposition of a continuous IO film. Subsequently, we present high-resolution scanning electron microscopy (SEM) of assembled colloids over large areas, which provides a detailed view of the evolution of the assembly process, showing that the organization of the colloids is initially dictated by the meniscus of the evaporating suspension on the substrate, but that gradually all grains rotate to occupy the thermodynamically most favorable orientation. High-resolution 3D transmission electron microscopy (TEM) is then presented together with analysis of the wetting of the templating colloids by the matrix precursor to provide a detailed picture of the embedding of metallic nanoparticles at the pore–matrix interface. Finally, the resulting properties and applications in optics, wetting, and catalysis are discussed, concluding with an outlook on the future of self-assembled metal-oxide-based IOs.

Pulmonary Pharmacokinetics of Polymer Lung Surfactants Following Pharyngeal Administration in Mice

We have recently discovered that pulmonary administration of nanoparticles (micelles) formed by amphiphilic poly(styrene-block-ethylene glycol) (PS-PEG) block copolymers has the potential to treat a lung disorder involving lung surfactant (LS) dysfunction (called acute respiratory distress syndrome (ARDS)), as PS-PEG nanoparticles are capable of reducing the surface tension of alveolar fluid, while they are resistant to deactivation caused by plasma proteins/inflammation products unlike natural LS. Herein, we report studies of the clearance pathways and kinetics of PS-PEG nanoparticles from the lung, which are essential for designing further preclinical IND-enabling studies. Using fluorescently labeled PS-PEG nanoparticles, we found that, following pharyngeal aspiration in mice, the retention of these nanoparticles in the lungs extends over 2 weeks, while their transport into other (secondary) organs is relatively insignificant. An analysis based on a multicompartmental pharmacokinetic model suggests a biphasic mechanism involving a fast mucociliary escalator process through the conducting airways and much slower alveolar clearance processes by the action of macrophages and also via direct translocation into the circulation. An excessive dose of PS-PEG nanoparticles led to prolonged retention in the lungs due to saturation of the alveolar clearance capacity.

A multi-feature predicting model of crown evolution involving material properties

We propose a new model for the crown evolution after a single drop impacts on a thin film. In contrast with the existing models that mainly focus on the status of well-developed crown or the bottom radius evolution, multiple features are provided in our model, including the temporal evolution of the crown radius, height, velocity, and the characteristic time when the crown reaches its maximum height. Both the fluid viscosity and surface tension are considered in this work rather than ignoring one or both of them as in previous studies, resulting in improved accuracy for crown development prediction. The new model can be applied for droplets of various fluids impinging on relatively thin films (0.1 &amp;lt; δ &amp;lt; 0.67). The reliability of the model is validated via comparing results with five cases of droplet impact experiments.